Binary Nomenclature

Name of organism: House fly

Question: Why is the house separated from the fly

Kingdom: Animalia

Phylum: Arthropoda (It has jointed appendages)

Class: Hexapoda or insecta (Hexa=six and poda =legs meaning six legs)

Order: Diptera (Di= two and tera means wings meaning two wings)

Family: Muscidae

Genus: Musca

Species: Domestica (Found in the house)

Note: butterfly is not a true fly so the “fly” is added to the “house” .House fly is true fly.

Rules for Naming Organisms

1.Authors name should come after the species name e.g. Musca domestica L. which means that Linnaeus
gave the name to the organism.
2.The generic name must start with a capital letter whiles the species name is started with a small letter to
differentiate it from other English words.
3.Always have to underline the names separately.
4.When typing botanical names must be italixed.
5.When another person is able to come out with a new generic name for an organism, the original authors
name is placed into parenthesis.
6.The name of the original author is totally replaced with another person’s name when that person is able to
come out with a new approved species name.

CHARACTERISTICS OF THE PHYLUM ARTHROPODA

Examples include: Insects, spiders, crayfish, crabs, millipedes, centipedes etc

a.Has jointed appendages

b.Entire body is jointed
c.It is bilaterally segmented-When body is divided from the head to the tail equally, the same body parts are
found on the same sides.
d.Ventrally located nerve chord with respect to the gut.
e.Possesses tough exoskeleton made up of chitin.
 CLASSES UNDER THE PHYLUM
ARTHROPODA

1.Crustacea
Examples: Spiny lobsters, Lobsters,
Scampi, crayfish, Crabs and Shrimp

a.Has two pairs antennae

b.Head and thorax fused together and is
known as cephalothorax and is covered by
a hard plate called carapace i.e. chitin made stronger. CRUSTACEANS
c.Five or more pairs of legs hence 10 or more legs.
d.Whole body is divided into 2

2. Arachinida
Examples: Spiders, Ticks, Pseudo scorpions,
Scorpions and Harvestmen.
a.Head well defined but not distinctly separated
from thorax.
b.They lack carapace
c.Has four pairs of walking legs

ARACHINIDS

3. Diplopoda (Millipedes)
a.No thorax
b.Has a small head in the rest of the body.
c.Looks very cylindrical.
d.Have 30 or more segments each segment bearing 2 pairs of
legs.
Note: Each segment bears 2 pairs of legs hence 30 segments
give 4 x 30 = 120 legs or 60 pairs of legs.

MILLIPEDE
4. Chilopoda (Centipedes)
a.Has no thorax
b.Each segment bears one pair of legs
c.Has 15 or more pairs of legs
d.The legs on the first segment after the head are
modified into poison claws
e.Has a small head and a long flat segmented
body

CENTIPEDE

5. Symphyla
a.Has a pair of antennae, a head and an abdomen
b.Tiny , whitish, soil dwelling organisms
c.12 or more pairs of legs

SYMPHYLANS

6. Hexapoda (Insecta)
i. Cosmopolitan distribution
ii. Range from small, 0.2mm (parasitic wasps) to very large, 7.5cm (goliath beetle)
iii. Appeared 250-340 million years ago
iv. 75%-85% of total animal population.
v. About 1 million species identified
vi. It is speculated that 4million new species are yet to be identified
vii. Thorax is three segmented: pro, meso and metathorax
viii. Each thoracic segment bears a pair of segmented walking legs ventrally
ix. Usually has two pairs of wings
x. Has antennae for sensing
xi. The wings, when present are borne on the mesothorax and the metathorax
xii. One pair of segmented antennae
xiii. One pair of compound eye
xiv. Each eye composed of several facets, each called ommatidium (plural ommatidia)

Examples of insects
 INSECT EXOSKELETON

 Used for protection against enemies and desiccation.

 For stimuli perception

INSECT INTERGUMENT

The insect body wall is made up of the epicuticle, exocuticle, endocuticle, epidermis and the basement
membrane/layer. The exocuticle and the endocuticle put together forms the procuticle. Of all the layers
only the epidermis is cellular (It has cells). The cuticle is heavily chitinised or sclerotised and rigid and
protects the insect against physical damage. The epicuticle in turn is made up of four layers namely
cement, wax, cuticulin, and a protein layer. The wax protects the insect against desiccation, cement
makes the body rigid, hard and strong. The cuticulin helps the insect forms colors that help to
camouflage/cryptic predators.
 GENERALISED STRUCTURE OF THE INSECT
LEG

Structure depends on function but is generally for walking.

Variously the insect leg is modified for
jumping/hopping, grasping, digging and climbing.

Legs composed of 5 parts namely coxa, trochanter, femur, tibia and tarsus.

Coxa attached to thorax in a small depression. It is freely movable through 270 0 . Only the tarsus is
segmented and terminates in a pair of claws usually one pad at the base or in between the claws. A pad in
between the claws is called arolium and that at the base is called pulvillus (pulvilli).

NB. The cockroach and other insects that sprint have cursorial legs that enable them to sprint. The
segmented tarsus is used for identification.

Note: The only part of the insect leg that is segmented is the Tarsus

AGRICULTURAL IMPORTANCE OF INSECTS TO MAN

Insects can both be beneficial and injurious.

There is a saying that “no insect no life”. It brings about pollination of higher plants, natural hybridization
therefore variety and stability.

Insects as pest also compete with man and other animals for the same resources. Man relies mainly on15
main crops (rice, maize, wheat, cowpea, groundnut, and soybean).

These crops are utilized by insect pest. Losses are greatest in the tropical and subtropics.

Beneficial Incsects

 Pollination of higher plants.

 Brings about natural hybridization therefore variety and stability.
 Helps to control injurious insects.
 MAN’S AGRICULTURAL ACTIVITIES THAT PROMOTE INSECCT POPULATION

1.Removal of primary or pristine forest. Natural ecosystem characterized by stable climax communities.
Destruction leads to changes in insect.
2.Monoculture: (Large scale) removes natural equilibrium established in a natural ecosystem.
3.Cropping intensification: (continuous monoculture) restricts dispersal and removes masking effect from
other crops. Energy expended in dispersal and searching for new host is reduced therefore pest numbers
and damage increases exponentially. E.g. plutella spp. And Hellula spp.
a. Crop spacing: The closer the plants to each other, the easier it is for the easier it is for the insects to move
from plants to plants. This is a result of little spacing between them and therefore insects have less space to
cover, less energy to use and has easy movement. Spacing alters factors like light penetration, canopy temp
and RH and soil moisture Maruca vitrata and Clavigralla spp. Increases with close spacing.
4.Land preparation: It has both negative and positive impacts on soil as well as plants. Affects weed and
other soil borne pest like beetle larvae (Grasshopper egg pods, shallow termite colonies etc.) which is
positive on the other hand, it increases colonization of legume fields by alate aphids (which responds to
green crop strips on the brown soil background) which is very negative. Aphids that have wings are called
alate. High population of winged aphids and harsh environment conditions influences the production of
winged aphids. Zero tillage helps reduce aphid colonization but helps cricket and millipede attack on
seedlings.
5.Development of new varieties: Aim of breeders are to breed for greater yield, more palatable taste, better
eye appeal, early maturity, increase in nutrient value and cooking quality. All these end up producing crops
of high protein content which enables pest to increase in numbers.
6.Introduction of new plants to new areas: The crop may become host to new pest.
7.Accidental introduction of pest: This comes in two forms thus exchange of planting material and food aid.
For instance Prostephanus truncates in maize aid to Tanzania (1970s) entered Ghana through Togo in 1984
popularly known as LGB. When these insects are introduced because there are no natural enemies they
become uncontrollable in their new areas. Prostephanus truncates (Larger GB) and Rhyzopertha dominica
(Lesser grain borer)
8.Soil nutrients depletion/amendments/amelioration: Aphids on plants on high nitrogen content produce
three times more than those on plants with less nitrogen. Increase dose of Mg increases incidence of purple
scale (Lepidosahes beckii) on citrus.
9.Over reliance on Pesticides: Destroys natural enemies and increases resistance of pest. E.g. BPH
(Nilaparvata lugens) and pesticide use in S.E Asia. Clavigralla spp. And pesticide use in Ejura.

10. Non-synchronous and late planting

 INSECT DEVELOPMENT

They develop from eggs. Subsequent stages go through different changes.

Metamorphosis: Changing processes between the egg and adult.

BIRTH IN INSECT

Four forms of birth in insects namely, oviparity, ovoviviparity, viviparity/larviparity and

parthenogenesis.

Oviparity: Egg laid and hatched outside the body of the female insects.

Ovovivoparity: Egg hatched in the common oviduct inside the body of the insect. Young ones do not
receive nourishment from the mother. Egg hatches into a nymph and resemble the adult, begins to feed
immediately after birth. Young insect is extruded by the mother.

Viviparity/Larviparity: Hatching of eggs take place in the female in the common oviduct into larvae.
Larvae get nourishment from mother. Matured larvae laid into moist soil where they pupate within 2 hours
or laid into putrefying matter where development may continue for a while before pupation. E.g. Tsetse
flies, blow flies.

Parthenogenesis: Embryonic development without fertilization usually produces one sex i.e. males or
females. Determines the fate of the individual in social insects(Determines whether Ants, Bees, Termites
will become a worker, soldier queen or king). When female aphids do not get males, they use this process.

Insect Cycle

 Two main cycles: Egg…Larva…Pupa…Adult (This take place in viviparity) and Egg..Nymph…
Adult (Ovoviviparity)
 Other cycle: Egg…Adult

METAMORPHOSIS

Eggs of insect are either laid near, in or on the food source. Young feed ravenously and increase in size but
the size to which it’s can increase is limited by the chitinous exoskeleton. Increase in size is therefore
accomplished by the shedding of chitinous exoskeleton which is referred to as moultting/Ecdysis. A rapid
expansion of the new elastic cuticula which hardens after several hours comes after moulting. An instar is
the stage between any 2 moults . E.g. L1, L2, L3, L4, PUPA has four instar stages. Instar stages in insects
varies but each has its specific number of instars. Generally 4 or 6 moults occur. Changes in insects from
egg to adult do not follow the same pattern.
 4 MAIN TYPES OF METAMORPHOSIS

 Ametabolous development (no metamorphosis): Egg- Young- Adult. No marked difference between
the young and the adult. All are wingless e.g. silverfish, Lepisma saccharina (Thysanura) Springtails
(collembola)
 Hemimetabolous development (incomplete metamophosis) E.g. Ephemeroptera (Mayflies) odonata
(dragon flies) and plecoptera (stonefish). Immature stages called nymphs or naiads. There are typical
hemimetabolous: Egg- nymph- adults. Nymphs do not resemble adults and development in water. Adults
are aerial. Nymphs breathe by tracheal gills.
 Paurometabolous. Egg- nymph- Adult (gradual metabolous). A form of incomplete metamorphosis.
Nymphs resemble adults in general body forms but lacks wings and external gernitalia. Each succeeding
moult resemble the adult more. Both adult and nymph feed on the same resources. Wing buds appear in last
2 nymphs e.g. grasshopper, Hemiptera
 Holometabolous (complete metamorphosis/heterometamorphosis) Egg- larvae- pupa- adult/imago.
All stages differ from each other. Larval stages feed voraciously and increase in size. Larvae have modified
chewing mouthparts. Larvae known by various names in different orders. E.g. coleoptera=grub,
Lepidoptera=caterpillar, Higher diptera=maggot. Wing pads develops internally in the larva. Mature larvae
refuses to feed and changes into pupa often a period of inactivity. Pupa generally inactive and does not feed
except e.g. mosquito pupa (aquatic, mobile). Marked physiological and morphological changes occur in
pupa. Pupa=Chrysalis in Lepidoptera (butterflies). May spin cocoons as in moths or hide in soil or under
tree barks.

INSECT ORDERS OF AGRICULTURAL IMPORTANCE

ORTHOPTERA (straight wings):

Includes grasshoppers, crickets, walking sticks etc.
1. All undergo paurometabolous metamorphosis.
2. Have well developed mandibulate mouthparts.
3.Antennae are filiform (thread-like) and many segmented.
4. Forewings long, slender and leathery with many veins and called TEGMEN (tegmina). Forewings may
either be reduced or even absent. Hind wings are wider than forewings and are membranous and are used
for flight. At rest the hind wing is folded as a fan (pleated) under the terminal.
5.Hind femur enlarged and elongated.
Cera well developed but short and unsegmented. Many species have long ovipositor (Only in females)
sometimes as long as a body. Cerci located at the posterior end of the abdomen.

NB: Ovipositor present only in females and used only to lay eggs. Cerci has a sensory function for sensing.
 SOUND PRODUCTION IN ORTHOPTERA

Most of them produce sound “sing” especially the cricket mostly the males. Sound (stridulation) is achieved
by rubbing of one part of the body against another. Singing orthoptera usually have auditory organs
(eardrums) or tympana located:

 On the side of the abdominal segment. E.g. Acrididae (Grasshopper).

 At the base of the front tibiae E.g. Tettigonidae and Gryllidae (Crickets)

ROLE OF SONGS IN THE ORTHOPTERA

Stridulation in orthoptera is used for:

 To attract/call mates
 For alarm or distress call
 For warning or intimidation or territorial songs
 To raise fighting or war songs
 Combat songs

IMPORTANT FAMILIES OF ORTHOPTERA

1. ACRIDIDAE (short horned grasshoppers)

a.Antennae short and reach only the pronotum (Refers to the upper part of the prothorax and shorter than the
body)
b.Tympanum on side of first abdominal segment.
c.Head not covered with pronotum
d.Hind femur large and elongated adapted for jumping or hopping
e.3 Segmented tarsi
f. Short ovipositors
g.Males sing only during the day
2. PYRGOMORPHIDAE (Variegated
grasshopper) ACRDIDAE
a.Antennae not beyond pronotum
b.Pronotum color shaped and well developed
c.Hind femur enlarged as in Acrididae
d.3 Segmented tarsus
e.Tympanum on side of abdominal segment
f. Adult and nymph usually brightly colored
yellow, black, red with white
g.When threatened produce fowl smelling
chemical
h.Usually sluggish even though adults fly

PYRGOMORPHIDAE

3. TETTIGONIDAE (Long horned

grasshoppers and katydids)
i. Head not covered by pronotum e.g.
conocephalus spp.
ii. Antennae reach far beyond pronotum
sometimes 2 times longer than the insect body
iii. Tympanum on front tibiae
iv. Tarsi four segmented
vi. Ovipositor sword like/sickle shaped
TETTIGONIDAE

4. GRYLLIDAE (cricket)
a.Antennae much longer than pronotum
b.Fore wings bent down sharply at sides of body
c.Tympanum on front tibiae
d.Hind femur enlarged for jumping
e.Tarsi 3 segmented
f. Ovipositor spear shaped
GRYLLIDAE
 ECONOMIC IMPORTANCE OF ORTHOPTERA

 Both nymphs and adults are serious crop pest

 Almost all phytophagous
 A few predatory (facultative) e.g. concocephalus longipennis
 Phytophagous ones have well developed mandibulate mouth parts
 Damage leaves and stem especially
 Some especially Acrididae and pyrgomorphidae exist both in solitary and gregarious phase
 Gregarious phases locust are devastating e.g. Schistocerca gregaria (desert locust) Locusta migratoria
migratoriodes (migrating insects) locust.

Aggregation formed by nymphs are called hopper bands and those by young or premature adults are called
swarms.

FORMATION OF AGGREGATIONS

1. Oviposition is synchronized and occurs in egg fields where millions of females came together to lay eggs
in soil of right moisture content.

2. The females can together under the influence of aggregation hormones.

3. Nymph emergence also synchronized.

4. Newly emerged nymphs aggregate through tactile responses and the innage urge to move in the same
direction in response to movement of the eearths major air masses

5. Young adults aggregate through tactile, sight, chemical responses as well as in respond to movement of
the earths major air masses.

DAMAGE BY ORTHOPTERANS

1. Earliest recorded damage by swarms of desert locust was before the exodus of the Jews from Egypt
(300 BC)
2. Another plague in 125 BC caused 800000 people to perish in Cyrenaica and 300000 in Tunisia.
3. Hoppers consume at least own body weight as early instars.
4. Actively migrating immature adults (swarms) need at least own weight 2 – 3g of fresh vegetation
daily.
5. A swarm constitute not less than 50 million individuals km-2 .
6. Hence a swarm of 10km2 would consume about 1000 tons of fresh vegetation daily on migration.
ORDER ISOPTERA

1. Isoptera means same wings/wings of the same size.

2. Classified as social insects and lives in groups with specific functions for each individual.
3. Colonies lives in nests or termitaria.
4. Exhibit caste system and has at least 3 caste viz reproductive/royals, workers and soldiers.
5. Apart from the adult reproductive all other morphs are wingless.
6.Wings when present are in two forms membranous with numerous vein like wrinkles.

TERMITE CASTE
1. Reproductives
A Primary Reproductive (kings and queens)
1. Most highly developed individuals
2. Have fully developed functional sexual organs
3. Possess 2 pairs of fully developed wings
4. A pair of compound eyes usually heavily pigmented
5. Body very dark in (darkest caste)appearance
6. Females often larger than males
7. They are produced in large numbers periodically and leave the colony in swarms especially at warm
evenings following a rainy day to proceed on nuptial flight.
8. Males and females pair up during flight, mate and return to establish own colony as king and queen.
9. The pair shed their wings (wings break off along a weakened line at the base leaving only the stubs
attached to the thorax)
10. Female leads male to find suitable place to establish colony.
11. They stay together for life
12. Fully matured queen a 10cm long can lay up to 300000 eggs per day.
13. The king and queen live in a royal chamber accessible to only young worker who tend the royals.
14. Royal chamber found at the center of the colony e.g. half the height of the termitarium below the
surface.

B Secondary Reproductive
They augment or take over the role of the primary king and queen when they die. They are (Brachypterous)
e.g. possess short nonfunctional wings and their body less pigmented than the primary reproductive. Eyes
are also smaller than those of the primary reproductive.
2. Workers
a.They are sterile adults and majority of nymphs (All
nymphs except instars 1 and2)
b. Are the smallest of all the caste but the most numerous?
c. Are pale in color (sometimes whitish) and all are
wingless (apterous)
Worker
d. Virtually blind (Lack compound eyes)
e. Have small mandibles but chew powerfully and cause the
damage, work 24hours, hence do not live long.
f. Collect food and feed all the caste and newly hatched.
g. Construct nests, galleries, funnels and passages.
h. Construct and care for fungus gardens which serve as food.
3. Soldier
A. MANDIBULATE SOLDIER
• Sterile adults with greatly enlarged, heavily sclerotized,
heads and mandible.
• When fully developed they are fed by workers.
Mandibulate Soldier
• Larger than workers and usually blind.
• Defend by either attacking and capturing intruder or use
large head to prevent entry of enemy.
B. NASUTUS SOLDIER
Head prolonged anteriorly (prognathous) into a snout.
Squirts sticky secretion through snout to immobilize or
paralyze intruders.

Nasutus Soldier

COMPARISM BETWEEN ANTS AND TERMITES

Ants Termites
Hymenoptera : Formicidae Isoptera : Termitidae
Antennae mostly curved or elbowed (genticulate) Antennae mostly monilliforme
Hind wings smaller than fore wings Both hind wing and fore wing same in side
Pedicel or petiole present between abdomen and thorax Thorax joined broadly to abdomen

Workers are the sterile females Workers are sterile adults and nymphs
Colony is defended by workers by stinging Colony defended by soldier caste
Hard bodied and dark coloured Soft bodied and light coloured
Workers found on soil surface and thus are called epigaec Workers subterranean or in wood and earthen
tunnels
Scanvengers and pedators Phytophagous
Feed mostly on proteinaceous (animal) tissue Feed mostly on cellolose containing materials
INSECT BODY
Structures on the Head
 A pair of compound eye or simple
eye.
 A pair of antennae.
 A mouth path.

Structures found on the Thorax

 Beas three pairs of legs (each of the
segment bears a pair of legs)
 Wings (1 or 2 pairs). NB. Some insect don’t have wings
 The thorax is divided into three parts namely: Prothorax, Mesothorax and Metathorax.
Facts
 Prothorax never bears the wing
 Wings are born on both metathorax and mesothorax but when one pair of wing is present, they
are born on the mesothorax.
 Each of the segments bear a pair of legs
 The mesothorax is segmented into the following parts: Prescutum, Scutum and scutellum.

Abdomen
This is the part that bears the reproductive structures.s
ORDER HEMIPTERA
Formerly considered as two Orders: Homoptera and Hemiptera but now put together as one Order:
Hemiptera but subdivided into three suborders namely: Auchenorryncha, Stenorryncha and
Heterotera.
 Former Homoptera now reduced to two suborders:
 Auchenorrhyncha: The cicadas (leafhoppers) and planthoppers.
 Stenorryhncha: Psyllids, whiteflies, scale insects(armoured scale and softscale)

 Former Hemiptera now reduced to:

 Heterotera(true bags): The most important characteristics of the Hemiptera is the piercing
and sacking mouth path modified into a sacking tool called Rostrum. The sucking mouth path
contains four sucking tubes or stylet two each of mandibles and maxillae.
Mouth Paths
1. Mandibles (one pair)
2. Maxillae (one pair)
3. Labrum (upper lip)
4. Labrum (lower lip)
5. Hypopharyns

TYPES OF MOUTH PATHS ORIENTED TO THE HEAD

1. Opisthognathous: Mouth path perpendicular to the insect leg.
2. Prognathous: Mouth path is straight or projected forward.
3. Hypognathous: Mouth path parallel to the insect leg or downwards.

IMPORTANT FAMILIES OF THE ORDER HEMIPTERA

NB Each sub-order and their corresponding families will be studied
a) SUB- ORDER-AUCHENORRYNCHA
The rostrum originates from the posterior part of the head near prothorax hence the head and the
face are deflexed downwards. (Oposthognathous). The forewing is uniform and usually clear and
membranous. In some families the forewing maybe coloured and slightly leathery but uniform in
texture. They undergo parametabolous metaphorsis.

FAMILIES
 CICADELLIDAE (Leaf Hoppers or Cicadas) : The characteristics include:
a) Usually Slender and elongated with round heads sometimes pointed.
b) Double row of spines runs along the entire length of the hind tibia. ( figure 1a)
c) Examples include:
 1. Nephotettix modulates (leaf
hopper) –Found in Africa and
N. virescence.
2. Cofana spectra
3. Empoasca fabae (potato leaf
hopper)
4. Cicadulina mbila.
These insects attack food crop
and transmit many viral
diseases. E.g. Cofana spectra
attacks rice and transmit
RYMV (Rice Yellow Mosaic
Virus) while Cicaulina mbila
attacks maize and transmit
Maize Streak Virus (MSV)

 DELPHACIDAE (Plant hoppers)

a) Identified by the hind tibia possessing a large spur projecting inwards at
the junction with the tarsus.
b) Antennae 4 segmented; the first three are monilliforme while the fourth
segment is thin and filamentous.
c) Serious crop pest particularly of the plant family Gramminae.
d) They cause wilting and hopper burn.

 CERCOPIDAE (Spittle bugs)

a) They resemble leaf hoppers but are larger and more robust.
b) Hind tibia has one or two stout spines projecting and a
circlet of spines at their apex or junction with the tarsus.

HIND LEG OF CERCOPIDAE

 b) SUB-ORDER STENORRYNCHA
All stenorryncha secret honey dew. Some secret copiously (plentiful). Examples include Aphids, Mealy
bugs, and Whiteflies.

FAMILIES
 APHIDIDAE (Aphids and Plant lice)
a) Small sluggish soft body usually green but can be brown,
purple and black.
b) Found usually clustered on food source E.g. Aphis
craccivora, A. fabai and Megoura viciae
c) They are usually apterous (no wings) but alate (aphids
with wings) forms are produced when conditions become
limited.
d) In the alates, the fore wings maybe coloured and slightly
and uniform in texture.
e) Wings are usually curved over the abdomen like a roof.
f) Members produce honey dew resulting in a secondary infestation of plant host by molds. (Honey
dew serves as food for other microorganisms).
g) Have very prominent abdomen when disturbed.
h) A pair of cornicles (dorsal abdominal projectons near the posterior part of the body) present in
most members.

 ALEYRODIDAE(White flies)
a) Examples include Bemisia tabaci and Aleurodicus disperses.
b) They are small insect (1 – 3mm) long.
c) Adult have two pairs of functional wings.
d) Adult of both sexes are winged; and both wings are
broad in relation to size.
e) Adult wings are coloured with white powdery wax
hence difficult to control with contact insecticides.
f) First instars are crawlers and move on younger
leaves.
g) Later instars are called larvae and are sedentary and
resemble scale insect.
h) The penultimate intars does not feed and remains in
the esuvia (a protective shell that protect the pupae)
of the previous stage called pupa.
i) White flies undergo false halo-metabolous
metamorphosis. Egg—Nymph—Larvae—
Pupae—Imago (Adult).
j) They transmit many viruses. E.g. African
Mosaic Virus.

 COCCIDAE (Soft Scales)

a) Female are oval and usually convex with
smooth cuticle (at times covered with wax)
for protection.
b) Appear more like exudations or outgrowths
on plants.
c) At first sight, they do not resemble insects.

 DIASPIDIDAE (Armoured Scales)

a) Immature males and females and adult
females have layers of cast skins(exuviae)
and waxy secretions that form a hardscale.
b) Only adult males are winged.
c) All other stages are sedentary. E.g.
California red scale (Aonididiella aurantii)
and Aspidiotus spp both on citrus.

 PSEUDOCOCCIDAE (Mealy Bugs)

a) Characteristics white mealy or powdery wax covers entire insect.
b) Oval in shape sluggish and mostly sedentary.
c) First instars are very active and are called crawlers.
d) Constitute the dispersal phase.
e) Entire body margin is lined with short spines.
f) Some species have long anal filaments.
g) Examples mealy bugs:
  Citrus mealy bug; Planococcus citri
 Cocoa mealy bug; Planococcoides njalensis
 Mango mealy bug; Rastrococcus invadens
 Cassava mealy bug; Phenacoccus manihoti
Note the following about the order Hemiptera
Most hemipterans are serious crop pest both primarily and secondarily
Suck plant sap e.g. aphids, leaf hoppers and plant hoppers.
Transmit plant viruses e.g. cocoa swollen shot virus.
Honey dew attract and promotes growth of fungi mold that reduce photosynthesis of leaves
Attending ants also spread crawlers (1st intars) and pathogens from infected trees to others.

c) SUB-ORDDER HETEROPTERA (True bugs)

 Bugs are more abundant and more diverse in the tropics than elsewhere.
 Are generally plant feeders (Phytophagus).
 Some are predaceous on other insects.
 Other feed on man and other animals (as parasite).
 Most bugs produce disagreeable odours when threatened or to scare natural enemies.
 The true bugs possess two pairs of wings
 Possess Hemelytron (fore wings are leathery at the base but membranous at the apex.
 At rest the fore wings usually overlap at apex.
 A triangular plate or sheet called Scutellum is located between the base of the forewings.
 All have piercing and sucking mouthparts which arise antero-ventrally (Body more or less
flattened dorso-ventrally.

IMPORTANT FAMILIES OF THE ORDER HETEROPTERA

 PENTATOMIDAE(Sting Bugs)
a) Four segmented sucking mouthpart
b) Five segmented antennae
c) Scutellun is relatively large and triangular in shape, narrowing posteriorly.
d) Eggs are laid in cluster or rows in the host plants.
e) Number of eggs vary 100 to 1000 13.16 per inch.
f) Examples includes: Southern stink bug (Nezara viridula), the Green sting bug (Acrosternum spp),
Aspavia armigera, Piezodorus guildinii, Bathycoelia thalassina (on cocoa).
g) Generally plant feeders (few pradaceous).
h) All widespread and important pest of legumes (cowpea, soyabeans etc.), cotton and rice.
i) Feed on dry seeds and wild legumes.
  Feeding result in shriveled pods, which later drop, shriveled seed, distorted (malformed, unfilled)
seed, wrinkled seed, or discoloured depending on time of attack.
 Feeding punctures may also result in secondary infestation by NZERA VIRIDULA
pathogens mostly fungi.
 Unfilled seeds fail to germinate or lack vigor.
 Discoloured seeds and lint loose value.

NB ..Mention two bugs that are found on cocoa?

Ans Planocoides njalens and Bathycoelia thalassina

 COREIDAE (Squash bugs and Leaf footed bugs)

a) Leaf and antennae are 4 segmented
b) Ocelli (simple eye) are present.
c) Membranous part on the Hemelytron has many viens
arising from a single transverse basal vein.
d) Body elongated but thick.
e) Antennae or hind legs may be ciliated or flattened.
f) Body usually pubescent (hairy) or spinous
g) E.g. Leptoglossus spp, clavigralla tomentosicollis, C.
shadabi and Riptortus dentipes.
h) Are very important pest in legumes e.g. cowpea.

Leptoglossus spp
  PYRRHOCORIDAE (Red bugs and
Cotton Stainers.)
a) Often brightly multi-coloured red, yellow,
brown and white.
b) Antennae 4 segmented.
c) Lacks hair on the body.
d) Beak (rostrum) 4 segmented and extends as far
as and lies in a groove along the abdomen.
e) Example includes: Dysdercus spp (red bug)

Dysdercus spp (red bug)

Note the difference and similiarities btn coreidae and pyrrhocoridae.

 MIRIDAE (Plant bugs: Capsids i.e.

Akate )
a) Grayish brown or dark brown in colour
b) No ocelli (simple eye); 4 segmented beak
(rostrum).
c) antennae usually monilliforme and or elbowed
(geniticulate).
d) Examples include: Sahlbergella singularis,
Distantiella theobroma, Bryocorpsis laticollis,
Heopeltis schlutedeni (cocoa mosuito), H.
bergrothi.
e) They are important pest of cocoa and causes
die back.
  REDUVIIDAE (Assassin Bugs)
a) Rostrum is 3 segmented.
b) First segment rounded at base and curved
downwards.
c) Rostrum only extends up to and lies in a
longitudinal groove on prosternum.
d) Head elongated and produced into a pseudo-
neck (False neck)
e) Large prominent eyes.
f) 4 segmented antennae.
g) Forelegs maybe raptorial and bear many
spines.
h) Abdomen maybe wider than wings and
flattened dorso-ventrally.
i) Most are predators, others are blood sucking
and will bite man.
j) Inflict painful bite.
k) Examples include: Triatoma spp. This insect
transmits a protozoan trypanosome that
causes chagas disease
ORDER HYMENOPTERA (Ants, Bees, Wasps and Sawflies)
N.B ‘Hymen’ means membrane
a) Antennae 10 or more segmented.
b) Mouthpart used for chewing and lapping (sucking) in bees.
c) Two pairs of membranous wings with few veins.
d) Hind wings smaller than fore wings.
e) Hind wings attached to forewings by a row of tiny hooks on the anterior margin.
f) Ovipositor well developed in most families and often elongated and modified with poison glands
to sting. (Organ for defense and offense). Usually used to pierce or for egg production.
g) Tarsi are usually 4 segmented.
h) Hymenoptera commonly exhibit parthenogentic reproduction (A form of asexual reproduction.)
i) Unfertilized eggs develop into males while fertilized eggs develop into female.
j) Some parasitic wasps exhibit polyembryony where one fertilized egg develop into adults from 2 to
1000 viable cells.
k) They are found to leave in either solitary or social colonies where caste systems exist and thus
division of labour occur. E.g. ants, social wasps and social bees.
l) Workers are females which feed the young and maintain, clean and defend the colony (and only
lay eggs in some species.
m) Males or Drones only live for a short time and mate with the new queen.

CLASSIFICATION OF THE ORDER HYMENOPTERA

 2 Suborders which includes:

1. SYMPHYTA: Sawflies and Horntails

SYMPHYTA
2. APOCRITA: Bees,
Ants and Wasps
This suborder is differentiated from the former by their constricted
waist i.e. narrow waist. They have a narrow or constricted first
abdominal segment fused to thorax.

WASP
SUBORDER APOCRITA (Bees, Ants and Wasps)
The first abdominal segment is incorporated into
thorax variously known as Propodeon, Propodaeum
or Propodeum. The propodeon (first abdominal
segment) is fused with the Mesosoma (The last
thoracic segment).
 Constricted first abdominal segment.
 Ovipositor modified to pierce or sting. E.g.
Bees.
 Larvae are legless. E.g. Apis mellifera (Apidae family name). WASP

Constricted waiste (1st abdominal

segment also known as propodeum)

SUBORDER SYMPHYTA (Sawflies and Horntails)

a) Have abdomen broadly joined to thorax.
b) 2 segmented trochanter.
c) Thorax broadly joined to abdomen.
d) Well developed saw-like ovipositor in
females.
e) Larvae resemble caterpillar of the order
Lepidoptera but differ by possessing 6 or
more pairs of prolegs and without claspers.
f) Larvae are like caterpillars with thoraxic legs
and prolegs but possess 6-8 pairs of prolegs.
g) Prolegs lack claspers

NB The difference between the larvae of a Lepidoptera and that of Symphyta.

Answer
 Larvae of Lepidoptera (caterpillar) has prolegs numbering not more than 5 but the larvae of a
sawfly (symphyta) has more than 5 prolegs.
 Larvae of sawfly don’t have claspers but the caterpillar of Lepidoptera have claspers.
 IMPORTANCE OF THE ORDER HYMENOPTERA
1. Considered the most important order in insect class.
2. Contains the largest number on beneficial families either as pollinators (e.g. family Apidae) or as
predators of harmful insects.
3. Very important in natural and biological pest management.
4. They are parasite of eggs and larvae of other injurious insects.
5. They are predators of all stages of harmful or noxious insects and other arthropod orders.

ORDER LEPIDOPTERA (Butterfly and Moths)

1. These are small to large insects ranging from 2mm to 300mm wide spread.
2. Their bodies are covered with loose powder-like scales that give the adult Lepidoptera a smooth or
slippy feel.
3. Adult have two pairs of large wings (slender to broad) with relatively few cross veins.
4. Hind wings are shorter, broader and more rounded than fore wings.
5. Some female moths are brochyterous (short non-functional wings) while others are apterous
(wingless)
6. Adult Lepidoptera have a pair of prominent compound eye and a pair of ocelli (simple eye)
sometimes.
7. Long, many segmented clubbed or plumose (feathery) antennae.
8. All Lepidoptera have siphoning (long coiled sucking tube called proboscis) except the
microptergidae (Mandibulate mouthpart).
9. Proboscis is coiled when not in use and positioned under the head.

CLASSIFICATION
Two suborders namely:

 Jugatae (butterfly)
 Frenatae (Moths)
CLASSIFICATION BASED ON WING VENATION AND METHOD OF UNION OF THE TWO
WINGS

1. SUBORDER JUGATAE (Rhopalcera)

 Front and hind wings have similar venation or arrangement of veins.
 The two wings are held together by a small lobe called jugum at the base of forewing
jotting out form fore to hind wing.

2. SUBORDER FRENATAE (Heterocera)

 Hind wings are smaller than fore wings and with a reduced venation.
 Wings are held together by a spine (Frenunum) projecting form base to hind into
forewing.

DIFFERENCE BETWEEN BUTTERFLIES AND MOTHS

Butterfly (Jugatae) Moth (Frenatae)

Clubbed antennae. Tapered and feathery antennae.
Fore and hind wings joined by jugum. Fore and hind wings joined by frenunum.
Larvae body usually smooth. Body is hairy and the hairs may sting.
Pupa is naked. Pupa is enclosed in a silking cacoon.
Pupa variously coloured and often tuberculate. Pupa usually brownish and smooth.
Adult mostly diurnal (active during the day). Adult mostly nocturnal.
Pupa attached to substrate by cremaster Pupa usually hidden under tree bark, debris or soil.
d. Filiform e. Geniculate f. Lamellate

g. Moniliform
h. Pectinate